MONTPELIER — At least one Democrat is looking to turn up the heat on Gov. Peter Shumlin for his refusal to release information about how he plans to fund a universal single-payer health care plan.

Shumlin, who is under a statutory requirement to deliver a financing plan for his proposed Green Mountain Care health system in 2013, has yet to do so. He also told lawmakers this year that he would outline a menu of tax options to pay for the plan this spring.

But the governor retracted that promise last week, saying the plan is simply not ready. Shumlin said he wants to make sure his administration gets a workable plan together before releasing more details about the system he intends to launch in 2017.

“Last week, he said, ‘Nope, we’re not going to do it,’ and I got really mad,” said Arlington Rep. Cynthia Browning.

Browning, a fellow Democrat, has grown impatient. Wednesday, she called Shumlin’s refusal to offer more details a “dereliction of duty” and “policy malpractice.”

She wants to force the governor to reveal the administration’s financing plan, or at least what it has completed so far. She filed a public records request last week seeking the administration’s work.

They all “fall under the common law and constitutional doctrine of executive privilege because they reflect communications in the course of the governor’s decision-making process that may be withheld to protect and facilitate the governor’s consultative and decisional responsibilities,” Costa wrote.

The materials withheld are being used to continue development of financing options for the next legislative session, according to Costa.

“The withheld records are my ongoing policy development papers, including draft research, modeling, reference materials, and material used to provide periodic updates to the governor and his advisors,” he wrote.

“As you noted, the work is not complete,” he added. “I expect to continue my research and data collection and analysis for some time, working to develop proposals for the governor’s consideration and decision in conjunction with the next biennium.”

Browning said she is displeased with the response but expected it.

“They stiffed me,” she said.

Now she wants to introduce a resolution calling on Shumlin to release his financing plan to the House Ways and Means Committee by the end of the month. It calls for the committee to have subpoena power that would compel the governor to do so. Such authority has been used by the House only once, Browning said.

The resolution has “zero” chance of passing, Browning acknowledged, but she hopes to force a vote to put members on record.

“I want the body to address how to hold the governor accountable,” she said.

Getting to a vote is not likely either, though. Democratic House Speaker Shap Smith said last week that he would prefer the administration complete its work on a viable financing plan before it is released.

Browning, meanwhile, hopes to gather some co-sponsors for her resolution, including other Democrats. She said her colleagues would have to “think long and hard” before doing so, however. Signing on could result in being isolated, as Browning said her previous challenges to Democratic leadership have left her.

“We’re approaching shunning,” she said. “But if I don’t hold Democrats accountable … how will I ever have credibility when I try to hold Republicans accountable?”

A Shumlin spokesman said in an email Wednesday that the administration will release its plan when it is ready.

“Health care reform is integral to Vermonters and the state’s economy,” wrote Scott Coriell. “With something this important, the governor wants to make sure we take the time to get it right.”